Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Inorganic silicon containing component
Reexamination Certificate
1994-04-07
2002-04-02
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Inorganic silicon containing component
C510S445000, C510S460000, C510S466000, C510S486000
Reexamination Certificate
active
06365568
ABSTRACT:
A process for producing a solid cast silicate-based cleaning compositions which includes the step of combining appropriate concentrations of an alkali metal silicate, an alkali metal hydroxide and a source of water to form a reaction mixture that solidifies into a reaction product which is processable at temperatures below the melting point or decomposition temperature of the reaction product. The process provides for the rapid manufacture of a solid cast alkaline cleaning composition without melting of the cast composition. Incorporation of appropriate amounts of a combination of a polyacrylate and a phosphonate into the cleaning composition cooperate with the silicate present in the composition to form a threshold system which is effective for controlling precipitation of both calcium and magnesium in a use solution.
FIELD OF THE INVENTION
The invention relates to solid, cast, silicate-based detergent compositions, methods of manufacturing such compositions, and threshold systems useful in such compositions. Specifically, the invention relates to methods of manufacturing substantially uniformly dispersed, solid, cast, silicate-based, alkaline detergent compositions which do not require “melting” of any component the reaction mixture or the reaction product and which can include an effective threshold system.
BACKGROUND OF THE INVENTION
The advent of solid cast detergent compositions has revolutionized the manner in which detergents are dispensed by commercial and institutional entities which routinely use large quantities of cleaning solution. Prior to the advent of solid cast detergents, commercial and institutional entities were limited to either liquid, granular or pellet forms of detergent. However, because of the numerous unique advantages offered by solid cast detergents, the solid cast detergents, such as those disclosed in U.S. Pat. Nos. Re. 32,763, Re. 32,818, 4,680,134 and 4,595,520 quickly replaced the conventional liquid and granular detergents in the commercial and institutional markets.
The unique advantages offered by solid cast detergents include improved handling resulting in enhanced safety, elimination of component segregation during transportation and storage, increased concentration of active ingredients within the composition, and various others.
One method of manufacturing solid cast detergent compositions involves the steps of forming a homogenous melt of the detergent composition, casting the molten melt into a mold, and solidifying the melt by cooling.
Fernholz et al., U.S. Reissue Pat. No. 32,763 describes a method of manufacturing a solid cast detergent composition which involves the steps of (i) forming an aqueous solution of two hydratable chemicals, such as sodium hydroxide and sodium tripolyphosphate, (ii) heating the solution to a temperature of about 65° to 85° C., (iii) increasing the concentration of hydratable chemicals in the heated solution to produce a solution which is liquid at the elevated temperature but will solidify when cooled to room temperature, and (iv) casting the heated solution into molds for cooling and solidification.
While the solid cast detergents manufactured in accordance with the molten processes constitute a significant improvement over the previously known liquid and granular detergent compositions, the molten process is time consuming, requires large quantities of energy, and can result in deactivation of desirable operative cleaning components incorporated into the detergent such as bleaches, defoaming agents, enzymes, and tripolyphosphates if processing parameters are not closely monitored.
One effort to simplify and improve the molten process is disclosed in Copeland, et. al., U.S. Pat. No. 4,725,376 The Copeland patent describes a method of manufacturing a solid cast alkaline detergent composition capable of decreasing the extent of deactivation resulting from the manufacturing process. Briefly, the process disclosed by Copeland involves pouring an aqueous melt of a hydratable, alkaline, detergent component into a mold containing solid particles of a thermally-deactivatable detergent component such that the aqueous melt percolates through the interstitial void volume between the solid particles and-then solidifies to form a solid cast detergent composition containing homogeneously dispersed granules of the thermally-deactivatable detergent.
Gansser, U.S. Pat. No. 4,753,755, discloses a method for producing a solid alkaline detergent composition similar in mechanism to Fernholz et al.
Smith, U.S. Pat. No. 2,164,092, discloses a method for solidifying an aqueous alkaline solution by incorporating a metaphosphate into the alkaline solution under conditions capable of converting the metaphosphate to an orthophosphate and/or pyrophosphate with accompanying dehydration and solidification of the aqueous mixture.
While the processes disclosed by Gansser and Smith provide for the manufacture of solid cast detergent compositions, the process of Gannser additionally results in reaction mixtures which generally take several hours to solidify and require prolonged agitation to prevent segregation while the process of Smith is limited to phosphate-based detergents.
Accordingly, a substantial need exists for additional manufacturing techniques which can provide for the formation of solid cast detergent compositions without requiring the attainment of melt/decomposition temperatures.
SUMMARY OF THE INVENTION
The invention is broadly directed to a cast solid composition and methods for the production of solid cast silicate-based cleaning compositions which do not require melt phase processing. Specifically, the invention provides for the production of solid cast silicate-based cleaning compositions which rapidly solidify substantially simultaneously across the entire cross section of the reaction product. In the process, as a result of mixing and under conditions of mixing, a thermodynamically unstable liquid mixture is formed that can rapidly solidify into a thermodynamically stable solid. Because the cleaning composition includes silicate as the source of alkalinity, a synergistically effective threshold system may be incorporated into the composition for the purpose of preventing the precipitation of both calcium and magnesium ions.
The process combines appropriate concentrations of an alkali metal silicate or mixtures of silicates, an alkali metal hydroxide and a source of water to create a liquid or fluid reaction mixture which is processable at temperatures below the melting point or decomposition temperature of the reaction product and which forms a reaction product which is solid under processing conditions.
The product of the process of the invention typically comprises a hydrated silicate containing composition or mixtures of a hydrated silicate species thereof. The hydrated silicate materials can contain additional amounts of concentrated sodium hydroxide as part of the solid matrix. In the solidification processes involved in the invention, a silicate composition, optionally another silicate species, and sodium hydroxide, interact with a wash chemical to form a liquid reaction mixture that is thermodynamically unstable which becomes thermodynamically stable through a solidification process. In the solidification process, the materials react to alter the normaly fluid constituent ratios to different ratios that are normally solid at ambient temperatures. In such reactions, we have found that most processing mixtures with common ratios of ingredients, that two or more discrete hydration states are formed in the reaction product. We have found that the production of two or more hydration states can be characteristic of products made with this reaction. It should be understood that at certain “perfect” ingredient ratios, single hydration states can be formed. However, under most processing conditions and combinations of ingredients, two, three or more, discrete hydration states can be formed. Such hydration states can be identified using differential scanning calorimetry (DSC) wherein each hydration has its character
Mizuno Bill George
Oakes Tom R.
Olson Keith Edward
Tallman Dan N.
Ecolab Inc.
Gupta Yogendra N.
Merchant & Gould P.C.
Mruk Brian
LandOfFree
Process for manufacturing solid cast silicate-based... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for manufacturing solid cast silicate-based..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for manufacturing solid cast silicate-based... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2873648